Toroidal plasma rotation induced by fast ions without external momentum injection in tokamaks

摘要

The mechanism for fast-ion-induced toroidal plasma rotation in the absence of external momentum input reported in Perkins et al (Perkins F.W. et al 2001 phys. Plasmas 8 2181) is examined in detail, at the level of single particle orbits and their collisional evolution, with the aim at clarifying the physical processes involved. This mechanism may be a contributing factor to the toroidal plasma rotation observed during the injection of intense ion cyclotron resonance frequency (ICRF) waves in recent tokamak experiments. It is found that the pitch-angle scattering of fast- ion orbits is essential in order to spin the plasma toroidally in the co-current direction.